In existing wireless communication systems, a wireless terminal connects to a radio base station and thereby can access the Internet via a core network. At that time, the wireless terminal performs packet communication through a communication path (bearer) established between the radio base station it has connected to and a gateway apparatus provided in the core network. In order to provide the bearer, the radio base station and the gateway apparatus construct a tunnel by encapsulating packets. The tunnel that passes data packets is identified by tunnel identification information, which is set in the outer header of the packet.
For example, in the EPS (Evolved Packet System) using E-UTRAN (Evolved Universal Terrestrial Radio Access Network) described in NPL 1, a wireless terminal UE (User Equipment) can perform packet communication through an EPS bearer created between the UE and a P-GW (Packet Data Network Gateway). In this EPS bearer, logical paths for passing data packets that are terminated between a radio base station (eNodeB) and a S-GW (Serving GW) and between the S-GW and the P-GW, respectively, are called GTP-U (GRPS Tunneling Protocol for User plane) tunnel which is identified by a TEID (Tunnel Endpoint Identifier) in an outer header of a packet.
In a communication system as described above, an increase in mobile traffic can be dealt with by adding a S-GW and a P-GW as necessary.